What happened during Thursday's performance problems for Google? The company said that "an error in one of our systems caused us to direct some of our web traffic through Asia, which created a traffic jam." Renesys, which tracks Internet routing, has additional details in a blog post today.

Renesys says traffic was shifted to NTT, whose network received an influx of traffic bound for Google that would normally be routed through Level 3 and/or AT&T. At one point NTT's network was handling 85 to 90 percent of the traffic bound for Google, according to Renesys. Check out Martin Brown's analysis for more.

NTT America said that traffic flow may have shifted, but the problems were due entirely to issues at Google. "NTT's network was not the cause of Google's performance problems," said a spokesperson for NTT America, which maintains the company's network. "No traffic jam occurred at NTT."